Stratification of patient populations to improve therapeutic response rate is increasingly valuable in the clinical management of cancer patients. Farnesyltransferase inhibitors (FTI) are therapeutic agents that have utility in the treatment of cancers, such asperipheral T-cell lymphoma (“PTCL”). However, patients respond differently to an FTI treatment. Therefore, methods to predict the responsiveness of a subject having cancer to an FTI treatment, or methods to select cancer patients for an FTI treatment, represent unmet needs. The methods and compositions provided herein meet these needs and provide other related advantages.